MAGNETIC COMPONENT WITH ELASTIC MAGNETIC COMPOUND

Abstract

A magnetic component (100) includes a main body (1) made of a main body material and a magnetic plastic part (2) connected in a fixed position to the main body (1). The plastic part (2) is produced from a compound which includes a polymeric support material and magnetic particles embedded in the polymeric support material, and the main body material and the compound having different thermal expansion characteristics. The plastic part (2) has a contact surface by which it is connected in a fixed position to the main body (1), and at least 60% by weight, in particular between 60% by weight and 95% by weight of the compound consists of the magnetic particles and the compound is formed as an elastic material for preventing cracks from forming in the magnetic plastic part (2), in particular the main body material being metal and the main body (1) in particular in the manner of a sleeve, disc or shaft

Claims

1. A magnetic component (100) comprising; a main body (1) made of a main body material and a magnetic plastic part (2) connected in a fixed position to the main body (1), the plastic part (2) being produced from a compound which includes a polymeric support material and magnetic particles embedded in the polymeric support material, and wherein the main body material and the compound having different thermal expansion characteristics, and the plastic part (2) has a contact surface by which it is connected in a positionally fixed manner to the main body (1), wherein at least 60% by weight of the compound consists of the magnetic particles and the compound is formed as an elastic material for preventing cracks from forming in the magnetic plastic part (2).

2. The magnetic Magnetic component (100) according to claim 1, one polyamide, wherein the compound consists in particular of at least 84% by weight, wherein the compound has a linear thermal expansion coefficient which is at least twice as large as that of the main body material, and herein in particular the compound has a modulus of elasticity which is in a range from 10 GPa to 25 GPa.

3. The magnetic Magnetic component (100) according to claim 1, wherein the polymeric support material is a semi-crystalline thermoplastic, and the polymeric support material consists at least 80% by weight of at least one polyester and/or at least one polyamide.

4. The magnetic Magnetic component (100) according to claim 1, wherein the magnetic particles have a mean particle size of 0.5 .Math.m to 100 .Math.m.

5. The magnetic Magnetic component (100) according to claim 1, wherein the compound has a melt mass flow rate between 30 g per 10 minutes and 150 g per 10 minutes.

6. The magnetic Magnetic component (100) according to claim 1, wherein the magnetic plastic component (2) is configured to elastically absorb material stresses which occur in the compound due to the different thermal expansion behavior of the main body (1) and plastic part (2) over a temperature range of -10° C. to 100° C. when the temperature of the magnetic component (100) changes, while avoiding crack formation.

7. The magnetic Magnetic component (100) according to claim 1, wherein the compound has a tensile modulus of elasticity of 7 GPa - 30 GPa and/or a tensile stress of 30 MPa - 100 MPa and/or an elongation at break of 1% to 6%.

8. The magnetic Magnetic component (100) according to claim 1, wherein the plastic part (2) is connected to the main body (1) by the contact surface in static frictional contact and/or is connected to the main body (1) in a form-fitting manner.

9. A method of manufacturing of the main body (1), magnetic particles and a polymer powder for realizing a magnetic component (100) according to claim 1, the method comprising producing an elastic compound having at least 60% by weight of which consist of the magnetic particles and at most 40% by weight of polymer resulting from the polymer powder, and applying the compound to the main body (1) and attaching the compound thereto.

10. The method according to claim 9, wherein during the production of the compound, first melting the polymer powder, then adding adhesion promoters, lubricants, thermo-stabilizers and/or impact modifiers to the melted polymer powder, and adding the magnetic particles to the melted polymer powder.

11. The method according to claim 9, wherein producing the magnetic plastic part (2) by injection molding to the main body (1).

12. A method for producing an elastic magnetic compound for realizing a magnetic component according to claim 1, the method comprising: mixing magnetic particles with a polymer powder in such a ratio that, in the compound produced, the magnetic particles constitute at least 60% by weight of the compound and the polymers resulting from the polymer powder constitute at most 40% by weight of the compound.

13. The method according to claim 9, wherein producing the magnetic plastic part is by injection molding.

14. The magnetic component (100) according to claim 1, wherein between 60% and 95% by weight, of the compound consists of the magnetic particles.

15. The magnetic component (100) according to claim 1, wherein the main body material is metallic.

16. The magnetic component (100) according to claim 1, wherein the main body material is metallic and the main body (1) is configured as a sleeve, a disc or a shaft.

17. The magnetic component (100) according to claim 1, wherein the polymeric support material is a semi-crystalline thermoplastic, the polymeric support material consists at least 80% by weight of at least one polyester and/or at least one polyamide including at least one aliphatic polyamide, and wherein the polymeric support material is a blend comprising different polymers.

18. The magnetic component (100) according to claim 3, wherein the polymeric support material is a blend comprising different polymers.

Description

[0021] The invention is explained in more detail below with reference to six figures by way of examples of embodiments.

[0022] In the drawings it is shown by:

[0023] FIG. 1: various views of one embodiment of a magnetic component according to the invention in schematic representations;

[0024] FIG. 2: a view of a further embodiment of a magnetic component according to the invention in a schematic representation;

[0025] FIG. 3: a further embodiment of a magnetic component according to the invention in schematic representations;

[0026] FIG. 4: a further embodiment of a magnetic component according to the invention in schematic representations;

[0027] FIG. 5: a further embodiment of a magnetic component according to the invention in schematic representations.

[0028] FIG. 1, comprising FIGS. 1a and 1b, shows one embodiment of a magnetic component according to the invention in schematic representations. FIG. 1a shows a view of a cross-section of the magnetic component 100, FIG. 1b shows a schematic top view of the magnetic component 100. The magnetic component 100 has a main body 1 and a magnetic plastic part 2. The main body 1 is designed as a sleeve and has a recess in which the plastic part 2 is embedded. The plastic part 2 is produced by injection molding to the sleeve 1. The recess of the sleeve 1, in which the plastic part 2 engages, has the flats 10 shown schematically in FIG. 1b, which are formed by the outer contour of the recess and which ensure an improved form fit between the plastic part 2 and the main body 1. In FIG. 1a, the axis of rotation R associated with the main body 1 and thus with the magnetic component 100 is schematically drawn. From the combined view of FIG. 1a and FIG. 1b, with FIG. 1b showing a schematic top view of the magnetic component 100 along the axis of rotation R, it is apparent that there is a particularly advantageous form fit between the magnetic plastic part 2 and the sleeve 1, which effectively counteracts relative movement of the plastic part 2 and the sleeve 1 both along the axis of rotation R and perpendicular to the axis of rotation R, in particular also a rotation of the plastic part 2 relative to the sleeve 1 about the axis of rotation R, since the flats 10, which are formed by the outer contour of the recess of the sleeve 1, do not extend rotationally symmetrically about the axis of rotation R in a plane perpendicular to the axis of rotation R. In the described embodiment, the magnetic plastic part 2 comprises 90% by weight of ferritic hard magnetic particles having an average particle size of 1.5 .Math.m. The magnetic plastic part 2 further consists of 9% by weight of a polymer, which in the present case is formed by different polyamides, as well as 0.1% by weight of an adhesion promoter, 0.2% by weight of lubricant, 0.1% by weight of a thermo-stabilizer and 0.6% by weight of an impact modifier. As is generally advantageous, the impact modifier is a polymer that has been functionalized with maleic anhydride and thus interacts with the polymer of the polymeric support material only via a secondary valency bond. In the present case, a phthalate is used as the impact modifier, although, as is familiar to those skilled in the art, substances based on, for example, adipates or ionomers can also be used as impact modifiers.

[0029] In FIG. 2, a further embodiment of a magnetic component 100 according to the invention is shown in a schematic representation. In this embodiment, the main body 1 is formed as a metallic shaft with a recess in which the plastic part 2 engages. Both the main body 1 and the magnetic plastic part 2 are each rotationally symmetrical about an axis of rotation R shown schematically in FIG. 2, which is generally advantageous according to the invention. As explained for FIG. 1, the magnetic plastic part 2 in FIG. 2 is also injection-molded onto the outside of the main body 1 around the axis of rotation R. In preferred embodiments, in the example according to FIG. 2, corresponding flats 10 as shown in FIG. 1 can also be provided in the recess of the main body 1 formed as a shaft. The plastic part 2 is produced by injection molding from a compound consisting of 71.5% by weight of magnetic particles, presently ferrites, 18% by weight of a polymer, presently polyester, and 2% by weight of an adhesion promoter, 3% by weight of a lubricant, 2.5% by weight of an impact modifier and 3% by weight of a thermo-stabilizer. In the embodiment described in FIG. 2, a silane is used as adhesion promoter, a fatty acid is used as lubricant, an adipate is used as impact modifier, and a phenol is used as thermo-stabilizer.

[0030] FIGS. 3 to 5 show further embodiments of the magnetic component 100 according to the invention in schematic diagrams. In these embodiments, the main body 1 is respectively made of metal, in this case steel, and the magnetic plastic part 2 is made of a compound as explained in the embodiment in FIG. 1. The magnetic plastic part 2 is always manufactured by injection molding and is molded directly to the main body 1 on the outside and/or inside circumferentially around the axis of rotation R during the manufacturing process. The various embodiments differ only with respect to the geometry and arrangement of the main body 1 and plastic part 2 and the resulting position of the plastic part 2 relative to the main body 1. In the embodiment according to FIG. 3, comprising FIGS. 3a and 3b, the plastic part 2 is injection-molded to a flange of the main body 1 that is designed as a sleeve, the flange forming flats 10 in which recesses are provided, so that a particularly robust, positionally fixed fixing of the plastic part 2 relative to the sleeve 1 is possible. In the embodiment according to FIG. 4, comprising FIGS. 4a and 4b, the main body 1 is designed as a sleeve which has, on the one hand, outward bends 12 and, on the other hand, recesses 11 with tabs. The plastic part 2 is molded around the outside of the main body 1 in such a way that it accommodates the outward bends 12 and engages in the recesses 11, thus ensuring a particularly reliable positionally stable fixing of the plastic part 2 relative to the main body 1. In the embodiment according to FIG. 5, comprising FIGS. 5a and 5b, the main body 1 is formed as a sleeve which has a flange, wherein circular recesses 13 are provided in the flange, wherein the plastic part 2 is injection-molded onto the flange in such a way that it engages in the circular recesses 13 for ensuring a particularly reliable fixation of the plastic part 2 relative to the main body 1.

List of Reference Signs

[0031] 1 main body

[0032] 2 plastic part

[0033] 10 flat

[0034] 11 recess

[0035] 12 bend

[0036] 13 recess

[0037] 100 magnetic component

[0038] R rotation axis